What is Kawasaki Syndrome?

Kawasaki Syndrome is an illness that occurs in young children between the ages of
6 months and 12 years, with the average age being from 1 to 2 years. The illness
was originally described in Japan in 1967 by a pediatrician named Dr. Tomsaku Kawasaki.
He called the illness “Mucocutaneous Lymph Node Syndrome” because the disease involved
the skin, the mucus membranes (i.e., lips, tongue, mouth, and eyes), and often the
swollen lymph nodes in the neck.

The illness was first described in the United States in the early 1970s, and several
thousand cases are reported each year to the Center for Disease Control (CDC). The
disease involves inflammation of the eyes, the lips, the throat, and the skin. It
also causes inflammation of the blood vessels within the body. The inflammation
of the blood vessels can particularly affect the coronary arteries, resulting in
weakening of the artery wall and formation of coronary artery aneurysms.

What causes Kawasaki Syndrome?

The cause of Kawasaki Syndrome remains unknown despite research to identify the
cause. The illness appears to be an inflammatory/infectious disease since it involves
a high fever and a rash, and it occurs suddenly in otherwise healthy children. Blood
tests show a high white blood cell count, and other laboratory tests that measure
inflammation also are elevated, suggesting either a bacterial infection or a bacterial
toxin. Some experts feel that a virus or other infectious agent may cause the disease.

Who gets Kawasaki Syndrome?

This disease occurs in otherwise healthy children and most often strikes children
between the ages of one and two years. It can occur in children of any ethnicity;
however, there is a higher incidence of this disease in children of Asian ancestry,
whether or not they live in the United States or in Asia. Hispanic children and
African-American children have a higher incidence of this disease than Caucasian
children. The reason for these differences is not known at the present time.

How does Kawasaki Syndrome cause disease?

Currently, it is believed that the symptoms of this disease are caused primarily
by the body’s inflammatory response to the unknown agent that causes Kawasaki Syndrome.
The damage to the coronary arteries that may occur could be the result of some direct
action by the microorganism or the toxin, or it may be due to the body’s immune
response to whatever causes Kawasaki Syndrome.

What are the common findings?

Usually, the illness begins abruptly, with the onset of a high fever. In untreated
cases, the average duration of the fever is 10 days, much longer than is usually
seen in a viral infection. Within a day or two of the fever, the child develops
red, “bloodshot” eyes and red, cracked lips. A parent may notice a swollen lymph
node in the neck.

The child also develops a blotchy, flat rash over the body. The rash may be very
red and intense in the diaper area. The palms and the soles become bright red, and
the hands and the feet may be swollen. Often, the child is very irritable and difficult
to console. Vomiting and diarrhea also can occur; however, they are less common
than the fever, the rash, the red eyes, the red lips, and irritability. Fourteen
to 21 days after the start of the illness, parents may notice peeling of the hands
and the feet.

How is Kawasaki Syndrome diagnosed?

Since the cause of Kawasaki Syndrome is not known, there is no blood test that proves
that the patient has Kawasaki Syndrome. It is a clinical diagnosis, and the doctor
must try to prove that the patient does not have any other condition that would
require other therapy. There are many other causes of a rash and a fever in children;
therefore, the diagnosis of Kawasaki Syndrome can be very difficult. Viral infections
(including measles) can mimic this disease, as can reactions to antibiotics and
other medications.

An allergic reaction to a medication can produce both a fever and a rash. Certain
bacterial infections, such as scarlet fever and toxic shock syndrome, also can mimic
Kawasaki Syndrome. The diagnosis of Kawasaki Syndrome should be considered when
the clinical findings are present, the blood tests suggest significant inflammation,
and no other cause of the findings can be found. A pediatric infectious disease
specialist and a pediatric cardiologist should evaluate children who are suspected
of having Kawasaki Syndrome.

How is Kawasaki Syndrome treated?

Although the cause of this disease is not known, an effective treatment is available.
IVIG (intravenous gamma globulin) reduces the signs of inflammation in the body
and reduces the risk of development of coronary artery aneurysms. Before IVIG was
used for this disease, the risk of development of coronary artery aneurysms was
approximately 20%.

If IVIG is given within the first 10 days of the onset of Kawasaki Syndrome, this
risk has now been reduced to between 2% and 4%. High dose aspirin also is used initially
to reduce inflammation. Low dose aspirin is used in the later stages of the disease
to prevent any clots from developing in inflamed blood vessels.

In most children who are treated with IVIG, there are no complications. The fever
and the rash disappear, and the child returns to normal within one to two weeks.
Peeling of the fingers and the toes occurs in children whether or not they are treated
with IVIG. If a child develops coronary artery aneurysms, he/she will need to be
followed by a pediatric cardiologist, and may require long-term aspirin therapy
or other cardiac medications.

Since this is a relatively new disease, long-term follow-up on children (from 30
to 50 years) is not yet available. The short-term follow-up suggests that children
who recover from Kawasaki Syndrome and who have no cardiac abnormalities remain
healthy, active children.

How can Kawasaki Syndrome be prevented?

What research is being done?

Research on Kawasaki Syndrome is being conducted in the United States, in Japan,
and in many other countries around the world. Kawasaki Syndrome has been reported
from all continents. Hundreds of thousands of cases have occurred in children in
Japan. Research focuses on the possible cause of Kawasaki Syndrome, and on new therapies
for children who do not respond to IVIG.

Taubert, KA, Shulman, ST. Kawasaki disease. American Family Physician 1999;59,11:3093-3102.

About the Author

Dr. Anderson is an Assistant Professor of Pediatrics and Pediatric Infectious Disease
Specialist at the Children’s Hospital and University of Colorado Health Sciences
Center in Denver, Colorado.

Dr. Glode is an international expert on Kawasaki Disease. She is a Professor of
Pediatrics and Vice-Chair of the Department of Pediatrics at the Children’s Hospital
and University of Colorado Health Sciences Center in Denver.